Many pharmaceuticals are dispensed in mass produced tablet forms which are required to fulfil several requirements before being considered acceptable by the United States Pharmacopeia. In order to ensure that the amount of active ingredient in the tablets is within acceptable limits of the labelled amount, the Pharmacopeia requires that the finished dosage form be assayed. Chromatographic and spectrophotometric methods are widely used to assay the active ingredient in tablets. The test for "uniformity of dosage units" is designed to ensure that the variation in the amount of active ingredient between the individual tablets is within acceptable limits.